The present invention relates to circuit structures and in particular to structures in which integrated circuit chips are attached to a common substrate.
It has previously been proposed to attach integrated circuit chips to a substrate by the so called flipchip method. This method requires the provision of raised contact pads or bumps on the integrated circuit chip which are bonded in electrical contact to conductive tracks or pads on the common substrate. Hitherto, problems have been experienced in aligning the chips accurately on the common substrate to thus ensure that every contact pad or bump on each circuit chip makes contact with its corresponding track or pad on the substrate. In addition problems of differential expansion due to temperature changes have been experienced when the chips and the substrate have been of dissimilar materials.